a script with two different behavior on the same version of chrome

I'm not familiar with javascript but my boss would like me to solve something weird so I took some time to investigate, with no satisfaying answer so far. Problem is, we have a script (jQuery) which works perfectly on most of our computers except for two of them, on chrome exclusively. All with the exact same version of the browser (55.0.2883.87 m). The script is a slider (Flipster) with 4 slides, with 3 hidden on the faulty machines instead of 4 with one bigger on focus when everything goes according to plan. Anyway, you obviously won't be able to find the answer for me (and I don't ask for it) but what I may ask you is where I might start digging, if some of you ever faced such situation and found their way through this in some particular areas... Thank you for your attention!